1. Technical Field
The present invention relates to a climbing, device for a revolving tower crane having a climbing frame movable along the crane tower for climbing in and/or climbing down tower sections, wherein a guide is provided for the longitudinally movable support of the climbing frame with respect to the crane tower.
2. Description of Related Art
Revolving tower cranes are typically adapted to the increasing height of the structure by the installation of additional tower sections. This procedure is generally called climbing. To be able to climb in a tower section, the upper crane part, which can comprise a crane boom, is typically released from the topmost tower section and is held by a climbing frame which is axially displaceably supported at the crane tower. After releasing the connection of the upper crane part from the topmost tower section, said climbing frame is moved so far upward that a further tower section can be fit between the released upper crane part and the topmost tower section and the upper crane part can then be placed on it or a further tower section can be placed on after a further climbing up.
Said climbing frame can surround the crane tower at the outside in the manner of a sliding sleeve and can have a lateral introduction opening through which a further tower section can be inserted or can also be removed again on the climbing down. It is alternatively also known to support the upper crane part temporarily with a lateral offset to the tower on the climbing frame during climbing up and climbing down so that the tower is freely accessible at the upper side to be able to place tower sections on or to remove them there. Said climbing frame is also longitudinally displaceably supported at the crane tower or at its tower sections in this case.
To be able to temporarily support the upper crane part together with the boom securely only on the climbing frame during climbing up and climbing down and to be able to take up corresponding moments of tilt and bending moments, the climbing frame is admittedly longitudinally displaceably supported at the crane tower by means of a guide, but is supported in a manner stable with respect to tilt. Such moments of tilt can arise, on the one hand, by wind loads, but, on the other hand, for example also by the taking up and letting down of tower sections which are to be climbed in and to be climbed down and which can be taken up and let down by the hoisting means at the crane itself.
The longitudinally displaceable guide of the climbing frame at the crane tower can in this respect comprise transverse support elements, for example in the form of sliding metal plates, which are, for example, attached to the climbing frame and which can engage around the crane tower from different sides. Sliding metal plates can, for example, engage at the longitudinal bars or corner bars of the tower sections typically formed as lattice girders to guide the climbing frame at the crane tower longitudinally displaceably, but in a manner stable against tilt. Instead of such sliding metal plates, guide rollers can also be provided at the climbing frame which can, for example, roll off at the corner bars of the tower sections.
The document DE 20 2005 009 236 U1, for example, shows a climbing device for tower cranes of the named kind.
With previous climbing devices of the named kind, relatively strong wear has previously resulted along the contact surfaces of the tower sections. This is particularly serious, for example, with cranes which are used at wind turbines since such cranes have to be climbed up and climbed down in a short time. In addition, juddering, abrupt displacement of the climbing frame has occasionally occurred when said climbing frame cannot be started or taken out of operation without jumping due to so-called slip-stick effects or when shape tolerances or dimensional tolerances result at the tower sections, in particular at their transition regions, which are too large and which can results in microtilts or even in jamming tendencies of the climbing frame. Such jumpy movements of the climbing frame are, however, highly unwanted since the climbing frame supports the whole upper crane part, including the boom, during its travel movement.